Imam al-Hassan al-Basri rahimahu Llah said:
We laugh and yet – who knows? – perhaps Allah has looked at some of our works and said: “I will not accept anything from you.” Woe to you, son of Adam! Can you fight Allah? Whoever disobeys Allah is fighting Him. By Allah! I have met seventy veterans of Badr. Most of their garments were wool. Had you seen them you would have said they are crazy, and had they seen the best among you they would have said: “Those people will have no part in the Hereafter.” Had they seen the worst among you they would have said: “Those people do not believe in the Day of Reckoning.” I have seen people for whom this world was cheaper than the dust under their feet. I have seen people the like of whom would come home at night, not finding more than his own portion of food, and yet say: “I shall not put all of this into my belly. I shall certainly give some away for Allah’s sake.” Then he would give away some of his food in charity, even if he were more in need of it than its recipient.
– Narrated from `Alqama ibn Marthad by Abu Nu`aym in Hilya al-Awliya’ (1985 ed. 2:134) –